Gaynor Spencer

Associate Professor

Office: F222
Phone: ext 3391
E-mail: gspencer@brocku.ca

Education:
BSc (Hons), Physiology, 1990. University of Leeds, UK.
PhD Physiology,1993. University of Leeds, UK

RESEARCH INTERESTS:

My research focuses on the cellular and molecular mechanisms underlying synaptic plasticity in the nervous system. Changes at the synaptic level occur both during development and as a result of experience, in the form of learning and memory. Studying such changes in synaptic connections help us to understand how alterations in the brain relate to changes at the behavioural level.

In my laboratory, the research falls into two general areas:
1.the study of interactions between neurons regenerating in culture, and
2. investigation of the cellular mechanisms of learning and memory.

In both of these areas of study, we utilize the mollusc, Lymnaea stagnalis. 

1. Many neurons in the brain of Lymnaea are large, identifiable from one brain to the next, and their transmitters and synaptic connections have been described. When removed from the brain, they regenerate neurites in cell culture. At the end of each neurite is a growing tip known as the growth cone. These growth cones use signals in their environment to guide the growing processes to their appropriate targets. My studies investigate what signals may act on these growth cones and aim to determine how and why the growth cones respond in a specific manner. 

2. Operant conditioning is a form of associative learning commonly used by humans, and is a response-dependent form of learning (reward or punishment paradigm). Unlike classical conditioning, the cellular mechanisms underlying operant conditioning are not well understood. Using the respiratory behaviour of Lymnaea, we can operantly condition the animal, and investigate at the level of single identified neurons and their specific connections, what cellular changes occur during both learning and memory. 

Selected publications (2006 to present):

• Carter, CJ, Farrar, N, Carlone RL, Spencer GE (2010). Developmental expression of a molluscan RXR and evidence for its novel, non-genomic role in growth cone guidance.  Developmental Biology. 343:124-37
  
• Farrar, N, Dmetricuk JM, Carlone, RL, Spencer GE (2009) A novel, non-genomic mechanism underlies retinoic acid-induced growth cone turning. Journal of Neuroscience 29(45):14136-42.
  
• Khan AM, Spencer GE. (2009) Novel neural correlates of operant conditioning in normal and differentially reared Lymnaea.  Journal of Experimental Biology 212: 922-933.
  
• Dmetrichuk JM, Carlone RL, Jones TRB, Vesprini N, Spencer GE (2008). Detection of endogenous retinoids in the molluscan CNS and characterization of the trophic and tropic actions of 9-cis retinoic acid on isolated neurons. Journal of Neuroscience 28(48):13014-13024.
  
• Farrar NR, Spencer GE (2008). In pursuit of a turning point in growth cone research. Developmental Biology 318: 102-111.
  
• Dobson K, Dmetrichuk JM, and Spencer GE (2006). Different receptors mediate the electrophysiological and growth cone responses of identified neurons to applied dopamine. Neuroscience 141:1801-1810.
  
• Dmetrichuk J, Carlone R and Spencer G. (2006) Retinoic acid induces neurite outgrowth and growth cone turning in invertebrate neurons. Developmental Biology 294:39-49.
  
• van Kesteren RE, Carter C, Dissel HMG, van Minnen J, Gouwenberg Y, Syed NI,  Spencer GE, and Smit AB  (2006). Local synthesis of actin-binding protein b-thymosin regulates neurite outgrowth. Journal of  Neuroscience. 26: 152-157
  
• Lowe MR and Spencer GE. (2006) Perturbation of the Activity of a Single Identified Neuron Affects Long-Term Memory Formation in a Molluscan Semi-intact Preparation. Journal of Experimental Biology 209: 711-721.

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